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A series of linear regression models were used to examine how different aspects of cognition, including sustained attention and traditional measures of executive functioning, related to gait speed while controlling for a variety of physical and vascular risk factors. Among all predictors, gradCPT accuracy explained the most variance in gait speed (R 2 = 0.19, p less then 0.001) and was the only significant predictor (β = 0.35, p = 0.01) when accounting for executive functioning and other physical and vascular risk factors. The present results indicate that sustained attention may be uniquely sensitive and mechanistically linked to mobility limitations in middle-to-older adults.Many older adults have difficulty understanding speech in noisy backgrounds. In this study, we examined peripheral auditory, higher-level auditory, and cognitive factors that may contribute to such difficulties. A convenience sample of 137 volunteer older adults, 90 women, and 47 men, ranging in age from 47 to 94 years (M = 69.2 and SD = 10.1 years) completed a large battery of tests. Auditory tests included measures of pure-tone threshold, clinical and psychophysical, as well as two measures of gap-detection threshold and four measures of temporal-order identification. The latter included two monaural and two dichotic listening conditions. In addition, cognition was assessed using the complete Wechsler Adult Intelligence Scale-3rd Edition (WAIS-III). Two monaural measures of speech-recognition threshold (SRT) in noise, the QuickSIN, and the WIN, were obtained from each ear at relatively high presentation levels of 93 or 103 dB SPL to minimize audibility concerns. Group data, both aggregate and by age decade, were evaluated initially to allow comparison to data in the literature. Next, following the application of principal-components factor analysis for data reduction, individual differences in speech-recognition-in-noise performance were examined using multiple-linear-regression analyses. Excellent fits were obtained, accounting for 60-77% of the total variance, with most accounted for by the audibility of the speech and noise stimuli and the severity of hearing loss with the balance primarily associated with cognitive function.Background Postural control and cognition are affected by aging. We investigated whether cognitive distraction influenced neural activity differently in young and older adults during a game-like mediolateral weight-shifting task with a personalized task load. Methods Seventeen healthy young and 17 older adults performed a balance game, involving hitting virtual wasps, serial subtractions and a combination of both (dual-task). A motion analysis system estimated each subject's center of mass position. Cortical activity in five regions was assessed by measuring oxygenated hemoglobin (HbO2) with a functional Near-Infrared Spectroscopy system. Results When adding cognitive load to the game, weight-shifting speed decreased irrespective of age, but older adults reduced the wasp-hits more than young adults. Accompanying these changes, older adults decreased HbO2 in the left pre-frontal cortex (PFC) and frontal eye fields (FEF) compared to single-tasking, a finding not seen in young adults. Additionally, lower HbO2 levels were found during dual-tasking compared to the summed activation of the two single tasks in all regions except for the right PFC. These relative reductions were specific for the older age group in the left premotor cortex (PMC), the right supplementary motor area (SMA), and the left FEF. Conclusion Older adults showed more compromised neural activity than young adults when adding a distraction to a challenging balance game. We interpret these changes as competitive downgrading of neural activity underpinning the age-related deterioration of game performance during dual-tasking. Future work needs to ascertain if older adults can train their neural flexibility to withstand balance challenges during daily life activities.Neural compensatory mechanisms associated with broad cognitive abilities have been studied. However, those associated with specific cognitive subdomains (e.g., verbal fluency) remain to be investigated in healthy aging. Here, we delineate (a) neural substrates of verbal (phonemic) fluency, and (b) compensatory mechanisms mediating the association between these neural substrates and phonemic fluency. We analyzed resting-state functional magnetic resonance imaging from 133 right-handed, cognitively normal individuals who underwent the Controlled Oral Word Association Test (COWAT) to record their phonemic fluency. We evaluated functional connectivity in an established and extended language network comprising Wernicke, Broca, thalamic and anti-correlated modules. (a) We conducted voxel-wise multiple linear regression to identify the brain areas associated with phonemic fluency. (b) We used mediation effects of cognitive reserve, measured by the Wechsler Adult Intelligence Scale-Information subtest, upon the association between functional connectivity and phonemic fluency tested to investigate compensation. We found that (a) Greater functional connectivity between the Wernicke module and brain areas within the anti-correlated module was associated with better performance in phonemic fluency, (b) Cognitive reserve was an unlikely mediator in younger adults. In contrast, cognitive reserve was a partial mediator of the association between functional connectivity and phonemic fluency in older adults, likely representing compensation to counter the effect of aging. We conclude that in healthy aging, higher performance in phonemic fluency at older ages could be attributed to greater functional connectivity partially facilitated by higher cognitive reserve, presumably reflecting compensatory mechanisms to minimize the effect of aging.Cerebral white matter hyperintensities (WMHs) represent macrostructural brain damage associated with various etiologies. Selleck mTOR inhibitor However, the relative contributions of various etiologies to WMH volume, as assessed via different neuroimaging measures, is not well-understood. Here, we explored associations between three potential early markers of white matter hyperintensity volume. Specifically, the unique variance in total and regional WMH volumes accounted for by white matter microstructure, brain iron concentration and cerebral blood flow (CBF) was assessed. Regional volumes explored were periventricular and deep regions. Eighty healthy older adults (ages 60-86) were scanned at 3 Tesla MRI using fluid-attenuated inversion recovery, diffusion tensor imaging (DTI), multi-echo gradient-recalled echo and pseudo-continuous arterial spin labeling sequences. In a stepwise regression model, DTI-based radial diffusivity accounted for significant variance in total WMH volume (adjusted R 2 change = 0.136). In contrast, iron concentration (adjusted R 2 change = 0.
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